FUNCTION: [Summary is not available for the mouse gene. This summary is for the human ortholog.] This gene encodes a nuclear protein that interacts with hepatitis B virus X protein (HBX) and facilitates transcription of hepatitis B virus genes by the HBX transcription activator, suggesting a role for this interaction in the virus life cycle. This protein also interacts with SNF2H protein to form the RSF chromatin-remodeling complex, where the SNF2H subunit functions as the nucleosome-dependent ATPase, and this protein as the histone chaperone. [provided by RefSeq, Sep 2011]